US1775636A - Esters of alpha hydroxy-iso-butyric acid - Google Patents

Description

' ly large amounts of cheap petroleum hydrol atented Sept. 16, 1930 UNITED STATES CHARLES BOGIN AND CARSON W.

TION OF MARYLAND SIMMS, OF TERRE HAUTE, INDIANA, ASSIGNOBS TO COMMERCIAL SOLVENTS CORPORATION,

OF TERRE HAUTE, INDIANA, A CORPORA- ESTERS OF ALPHA HYDROXY-ISO-BUTYRIO ACID No Drawing.

Our present invention relates to new compositions of matter comprising the esters of alpha hydroxyisobutyric acid with monohydric alcohols having more than two carin which, the n-propyl, isopropyl, n-butyl, isobutyl, amyl, etc. radicals may be substituted for R. The butyl ester for example, has the following formula:

The n-butyl ester of alpha hydroxyisobutyric acid is a very mild and pleasant smelling liquid which boils at 1l0-114 C. under about 75 mm. pressure. It is insoluble in water and only very slightly hydrolized on long heating with water. It is an excellent solvent for nitrocellulose and due to this property can'be very advantageously 'employed in the production of nitrocellulose lacquers, such as brush tural lacquers, which require the use of solvents evaporating at fairly slow rates. Other properties, such as compatibility with gums and oils together with the fact that relativecarbo-n diluents and turpentine may be added to a solution of nitrocellulose in the said solvent without causing the precipitation of the nitrocellulose, add. to itsvalue as a solvent in the lacquer industry. The. n-butyl ester of alpha hydroxyisobutyric acid may also be advantageously used for other purposes.

The other esters of alpha hydroxyisobutyric acid with monohydric alcohols having more than two carbon atoms have, in general, properties similar tothose of the n-butyl ester and may be employed similarly.

The esters of alpha hydro-xyisobutyric acid with .alcohols containing more than two car bon atoms may be prepared in a number of ways. For example, alpha hydroxyisobutyric acid ma be obtained from acetone by the eyanhy rin reaction and the ester then lacquers or architec- Application fi1ed. May 12, 1928. SerialNo. 277,398.

prepared by esterifyin tained with the desired alcohol. The preparation of the normal propyl ester of alpha hydroxyisobutyric acid by this method will be described merely as an example of one method of obtaining our new compositions.

To 250 grams acid,.prepared by any suitable method, 160 grams ofnormal propyl alcohol and 200 grams of ben'zol are added and esterification effected by the aid of approximately 5 grams of sulphuric acid as a catalyst. The water produced by the esterification is removed from the reaction Zone as a component of a binary constant boiling point mixture'with benzol, the latter being separatedfrom the condensate and returned to the reaction mixture. When tests show that the esterification is practically complete, the reaction mixture is neutralized with concentrated sodium hydroxide solution. The desired. ester is then recovered by distillation in vacuo. propyl alpha hydroxyisobutyrate preparedas above described boils at 164 165? 0., has a density of 0.9639 at 20 C/20 C. and is soluble in water to the extent of about 10%.

The isopropyl ester of alpha hydroxyisobutyric acid, prepared in a similar manner to that described above, boils at 15015,3 6., has adensity of 0.9477 at 20 C./20 C. and is soluble inwater to the extent of about 15%;

Another" convenient method of obtaining the esters of higher boiling point is by alcoholysis, methyl, or preferably, ethyl alpha hydroyisobutyrate being reacted with the alcohol, the radical of which it is desired to substitute for the methyl or ethyl radical. The preparation of n-butyl alpha hydroxyisobutyrate' is described merely as an example of this method. Emampl ei' 12.0 gram mols of ethyl alpha hydroxyisobutyrate, 15.0 gram mols of nbutyl alcohol and 0.25 gram mol 95% sulhuric acid are heated in a flask provided with a fractionating column. Sufiicient heat is maintained under the flask to keep the vapor temperature at 80to 85 C. Under these conditions a reaction takes place between the n-butyl alcohol and the ethyl alpha hydroxyisobutyrate Wlllll the formation of.

PATENT OFFICE.

g the acid thus obof alpha hydroxyisobutyric The n ethyl alcohol and n-butyl alpha hydroxyisobutyrate. The removal of the ethyl alcohol, together with small amounts of other materials present from the reaction zone by distillation, allows the reaction to go to completion. The vapor temperature reaches 97 to 100 when the reaction is complete. The reaction mixture remaining in the flask is then cooled, washed with Water, then with sodium carbonate solution, and finally again with water. It is then dried with sodium sulphate and fractionally distilled. The first fraction thus obtained consists of n-butyl alcohol and water the second of n-butyl alcohol and n-butyl alpha hydroxyisobutyrate, and the last of the practically pure ester.

The isobutyl ester of alpha hydroxyisobutyric acid may be prepared in a manner similar to the corresponding n-butyl ester described above. It boils at approximately 173 C. at atmospheric pressure. It is soluble in Water to the extent of about 3% at ordinary temperature. Its density is 0.9447 at 20 C./20 C.

The amyl ester of alpha hydroxyisobutyric acid boils at 1901 C. at atmospheric pressure, has a density of 0.9350 at 20 C./20 C. and is soluble in water to the extent of less than 1%.

All of the compounds described above are practically colorless liquids which have rather mild, pleasant odors.

ow having described our invention, what We claim as new and novel is:

s new compositions of matter, esters of alpha hydroxyisobutyric acid, whose molecular structure is expressed by the following formula:

where R- represents the radical of a monohydric alcohol having more than two carbon atoms.

2. As a new composition of matter, the butyl ester of alpha hydroxyisobutyrio acid, whose molecular structure is expressed by the following formula: 7

OH: or:

o 0 CHa O o-o4m. In testimony whereof We aflEix our signatures.

CHARLES BOGIN. CARSON W. SIMMS.

C. and the liquid temperature C.